Determination of Residual Stress with Diffusion MR Method in Cortical and Trabecular Sections of Human Vertebral Bone Tissue

Abstract

Objective: The aim of this study was to develop a new method for the determination of residual stress by measuring diffusion coefficient in human vertebral bone tissue using the diffusion MRI method. Methods: For this study, 75 healthy individuals were recruited and divided into three groups. There were 25 individuals in each group. The age group consists the following: group 1, 15-20; group 2, 40-50; and group 3, 60-70. The vertebrae images of subjects were taken by diffusion MRI. Diffusion coefficient of cortical and trabecular regions was measured on these images, and the results were compared using the Kruskal–Wallis statistical method. Bone densitometry of all subjects was measured, and groups were compared using ANOVA. Results: The cortical and trabecular diffusion coefficients were compared in groups 1-3. Both diffusion parameters were significantly decreased in groups 1-3. This indicates a decrease in diffusion with increasing age. In the measurements performed with X-ray densitometry, dual energy X-ray absorptiometry (DXA) and Crush values were found to be increased significantly. No significant change was observed in bone mineral content (BMC), bone mineral density (BMD), T, and Z values. Cortical and trabecular diffusion coefficients were decreased with age. BMD and BMC values did not change, but DXA and Crush values were observed to increase with age. Although BMD and BMC values did not change, diffusion reduction may be associated with increasing age. Conclusion: The results of this study indicate that residual stress that causes nanocrush and later fragility in bone tissue can be determined by measuring diffusion coefficient through the diffusion MR method.